Granted Patent B2

US 9,249,487 · App. 13/827,918 · Granted Feb 2, 2016

Abstract

Claims (35)

1. A method comprising:

(a) casting an aluminum alloy having from 2.5-12.0 wt. % Zn and from 1.0 to 5.0 wt. % Mg, where at least one of the zinc and the magnesium is the predominate alloying ingredient other than aluminum;

(b) optionally hot working or cold working the aluminum alloy;

(c) after the casting step (a) and the optional step (b), solution heat treating and then quenching the aluminum alloy;

(d) after step (c), optionally working the aluminum alloy;

(e) after step (c) and the optional step (d), artificially aging the aluminum alloy, wherein the artificial aging step (e) comprises:

(i) first aging the aluminum alloy at a first temperature of from 330° F. to 530° F. and for a first aging time of from 1 minute to 45 minutes;

wherein the first aging comprises heating the aluminum alloy to the first temperature at a heating rate of at least 388° F. per hour;

(ii) second aging the aluminum alloy at a second temperature for a second aging time of at least 30 minutes, wherein the second temperature is lower than the first temperature.

2. The method of claim 1 , wherein the first temperature is from 350° F. to 460° F.

3. The method of claim 1 , wherein the first temperature is from 390° F. to 420° F.

4. The method of claim 1 , wherein the first aging time is not greater than 30 minutes.

5. The method of claim 1 , wherein the first aging time is not greater than 20 minutes.

6. The method of claim 1 , wherein the first aging time is not greater than 10 minutes.

7. The method of claim 1 , wherein the first aging time is at least 5 minutes.

8. The method of claim 1 , wherein the second aging temperature is from 5 to 150° F. lower than the first aging temperature.

9. The method of claim 1 , wherein the second aging temperature is from 10 to 100° F. lower than the first aging temperature.

10. The method of claim 1 , wherein the second aging temperature is from 10 to 75° F. lower than the first aging temperature.

11. The method of claim 1 , wherein the second aging temperature is from 20 to 50° F. lower than the first aging temperature.

12. The method of claim 1 , wherein the first aging temperature is about 400° F. and wherein the second aging temperature is about 360° F.

13. The method of claim 1 , wherein the method consists of steps (a), (c) and (e), optionally with step (d).

14. The method of claim 1 , wherein the aluminum alloy comprises up to 3.0 wt. % Cu.

15. The method of claim 1 , wherein the aluminum alloy comprises 4.0-5.0 wt. % Zn and 1.0-2.5 wt. % Mg.

16. A method comprising:

(a) casting an aluminum alloy having from 4.0-5.0 wt. % Zn and from 1.0 to 3.0 wt. % Mg;

(b) after the casting step (a), solution heat treating and then quenching the aluminum alloy;

(c) after step (b), artificially aging the aluminum alloy, wherein the artificial aging step (c) comprises:

(i) first aging the aluminum alloy at a first temperature of 400° F. for 1 to 20 minutes, or a substantially equivalent aging condition;

wherein the first aging comprises heating the aluminum alloy to the first temperature at a heating rate of at least 388° F. per hour;

(ii) second aging the aluminum alloy at a second temperature of 360° F. for 2 to 8 hours, or a substantially equivalent aging condition;

(d) optionally stretching the aluminum alloy, wherein the optional stretching occurs after the casting step (b).

17. The method of claim 16 , comprising:

(e) concomitant to or after the artificial aging step (c), forming the aluminum alloy into a predetermined shaped product.

18. The method of claim 16 , consisting of steps (a)-(c), optionally with step (d).

19. The method of claim 17 , consisting of steps (a)-(c) and (e), optionally with step (d).

Assignments (8)